Moringa oleifera Lam. Seeds as a Natural Solid Adsorbent for Removal of Ag-I in Aqueous Solutions

This work describes the sorption potential of Moringa oleifera seeds for the decontamination of Ag-I in aqueous solutions. Infrared spectroscopy was used for elucidating possible functional groups responsible for uptaking Ag-I. Sorption studies using Ag-I standard solutions were carried out in batch experiments as functions of adsorbent mass, extraction time, particle size and pH. The Ag-I was quantified before and after the removal experiments using flame atomic absorption spectrometry. Furthermore, based on adsorption studies and adsorption isotherms applied to the Langmuir model, it was possible to verify that M. oleifera seeds present a high adsorption capacity. The optimum conditions were: 2.0 g of adsorbent with particle size of 75-500 mu m, 100 mL of 25.0 mg L-1 Ag-I, extraction time of 20 min and pH at 6.5. The results show that Moringa oleifera seeds can be used for removing Ag-I in aqueous solutions.